This desert plant can be used to make rubber and grows with little water
Building subdivisions in the desert might seem like a poor choice when it comes to water conservation. All those kitchen sinks and showers. All those toilets. But in the Valley, about 89% of that water gets recycled.
When a farmer irrigates crops, the water all goes into the ground. So, researchers at the University of Arizona are working with farmers to find new ways to conserve.
On a hot summer day, University of Arizona assistant irrigation specialist Diaa Eldin Elshikha goes around an experimental field near Maricopa, where researchers pump groundwater into a pond, which feeds the irrigation pipes. They’ve planted two fields of cotton next to each other. One will receive drip irrigation, the other, flood irrigation.
“So, in this cotton irrigation experiment, we are testing two different systems,” he said. “We’d like to see how it would affect plant growth and yield.”
The researchers use weather data to calculate evaporation rates. Solar panels power a system that adjusts soil pH levels. When they want to monitor the crop, they use drones.
Ethan Orr, who oversees the program, says that while irrigation systems are important, they’re just one piece of the puzzle.
“We go out and we visit the farmer. We work with them, so we’re looking at soil health, we’re looking at productivity, because what I don’t want to do is create a mechanical solution that damages the soil and creates a generational problem of not being able to grow something 20 years from now,” Orr said.
One way to improve soil health and save water is to rest the ground. But farmers don’t make money from fallow fields.
Researchers have begun to look at different crop rotation systems. And different crops, such as guayule. The plant is native to the Chihuahuan Desert and can be used to make rubber.
“At the end of the day it’s a business,” said Debankur Sanyal, a soil specialist for UA. “For commercial farms, it’s a business for the farmer, so whatever they spend on it they want some money back, some profit.”
Arizona’s sunshine makes it a good place to grow crops.
“Farmers can grow two, three, four crops a year on the same ground, but, every time you grow a crop, you take something from the soil,” Sanyal said.
Guayule is different. It stays in the ground for two years before a single harvest. And it helps put back nutrients that other crops take away.
“So, guayule can rest the ground, and make money for the farmers,” he said.
Here’s the best part: It doesn’t use much water.
Bridgestone has invested millions to fund research in the crop. The chemistry of guayule rubber and rubber harvested in Asia is essentially the same, said Bill Niaura, executive director of sustainable innovation for Bridgestone Tires. He says the company has already made tires with it.
“We are currently using it in our Indy car tires for that race series,” Niaura said.
That’s Indy, as in the Indianapolis 500. While the company knows it can manufacture tires with guayule, the problem is growing the crop on an industrial scale.
“What we’re trying to do is create a new industry for North America. There is no North American natural rubber industry, and we’re trying to do that with a crop that’s not industrialized yet. So, just think about it, when was the last time a new crop came on the market, right?” Niaura said.
That means analyzing markets, seed production, harvest techniques, crop insurance and financing. Finding new ways to help farmers conserve water makes a lot of sense, says Orr, the department head. Agriculture brings a lot of benefits to the state, such as lower food costs, but the benefits go beyond that.
“Preserving ag helps mitigate the dust storms, the dust effects that we see on I-10; it also helps mitigate the heat island effect,” Orr said.
So, while agriculture uses a lot of water, it brings a lot of benefits to the state.
“Farming is extraordinarily valuable, but it must be done in concert with the ecosystem,” Orr said.
And with climate change making things hotter and drier, that will mean using less water.